Fig. 4. Relationship of p43 to La proteins. Parts of the predicted protein sequence of p43 (E.a.) are aligned with the respective regions of La proteins from human (H.s.), D.melanogaster (D.m.), the fission yeast S.pombe (S.p.) and S.cerevisiae (S.c.) (Chambers et al., 1988; Yoo and Wolin, 1994; van Horn et al., 1997). Amino acids in black shading are similar or identical in the majority of the five proteins (see Materials and methods). Numbers to the left and right of each of the sequences refer to their start and end amino acid positions, respectively. Top: alignment of the La motif regions. The three amino acids in p43 whose identity is uncertain due to lack of information on the exact location of the frameshift are underlined. The sequence shown here assumes the frameshift event at site 3 (see Figure 3). The phenylalanine residue conserved in La proteins is marked by an asterisk. Bottom: alignment of parts of the putative RRM region. The RNP2 and RNP1 submotifs are overlined.